Source : Webster's Revised Unabridged Dictionary (1913)

Improve \Im*prove"\, v. t. [imp. & p. p. {Improved}; p. pr. &
   vb. n. {Improving}.] [Pref. in- in + prove, in approve. See
   {Approve}, {Prove.}]
   1. To make better; to increase the value or good qualities
      of; to ameliorate by care or cultivation; as, to improve
      land. --Donne.

            I love not to improve the honor of the living by
            impairing that of the dead.           --Denham.

   2. To use or employ to good purpose; to make productive; to
      turn to profitable account; to utilize; as, to improve
      one's time; to improve his means. --Shak.

            We shall especially honor God by improving
            diligently the talents which God hath committed to
            us.                                   --Barrow.

            A hint that I do not remember to have seen opened
            and improved.                         --Addison.

            The court seldom fails to improve the oppotunity.
                                                  --Blackstone.

            How doth the little busy bee Improve each shining
            hour.                                 --I. Watts.

            Those moments were diligently improved. --Gibbon.

            True policy, as well as good faith, in my opinion,
            binds us to improve the occasion.     --Washington.

   3. To advance or increase by use; to augment or add to; --
      said with reference to what is bad. [R.]

            We all have, I fear, . . . not a little improved the
            wretched inheritance of our ancestors. --Bp.
                                                  Porteus.

   Syn: To better; meliorate; ameliorate; advance; heighten;
        mend; correct; recify; amend; reform.

Improve \Im*prove"\, v. t. [Pref. im- not + prove: cf. L.
   improbare, F. improuver.]
   1. To disprove or make void; to refute. [Obs.]

            Neither can any of them make so strong a reason
            which another can not improve.        --Tyndale.

   2. To disapprove; to find fault with; to reprove; to censure;
      as, to improve negligence. [Obs.] --Chapman.

            When he rehearsed his preachings and his doing unto
            the high apostles, they could improve nothing.
                                                  --Tyndale.

Improve \Im*prove"\, v. i.
   1. To grow better; to advance or make progress in what is
      desirable; to make or show improvement; as, to improve in
      health.

            We take care to improve in our frugality and
            diligence.                            --Atterbury.

   2. To advance or progress in bad qualities; to grow worse.
      ``Domitain improved in cruelty.'' --Milner.

   3. To increase; to be enhanced; to rise in value; as, the
      price of cotton improves.

   {To improve on} or {upon}, to make useful additions or
      amendments to, or changes in; to bring nearer to
      perfection; as, to improve on the mode of tillage.

Source : WordNet®

improve
     v 1: to make better; "The editor improved the manuscript with his
          changes" [syn: {better}, {amend}, {ameliorate}, {meliorate}]
          [ant: {worsen}]
     2: get better; "The weather improved toward evening" [syn: {better},
         {ameliorate}, {meliorate}] [ant: {worsen}]